A river sand substitute | Daily News


 

A river sand substitute

Construction  work in progress
Construction work in progress

Sri Lanka should seriously think of producing an eco-friendly variety of sand for the construction sector, which will help reduce dependence on river sand mining. What is needed is a Proper Action Plan to overcome the crisis situation faced with.

Finding an alternative to using natural sand in the construction industry is a major topic that has cropped up every so often …but still the issue has not got the due attention of the authorities. Although the country’s construction industry has had major successes throughout the last two decades – it is unfortunate – that sufficient discussions backed by scientific data and expert knowledge have not taken place to find reasonable solutions for sand supply for construction industrial needs, the industry representatives say.

The need for an alternative was also reemphasized by the Chamber of Construction Industry of Sri Lanka (CCI) recently, in a proposal submitted to the President.

President CCI, Nissanka Wijeratne said it is a paramount need to establish ways to supply crushed rock, earth and sand for construction projects as the current supplies are inadequate.

The Chamber said in the proposal to the President, “Difficulties in identifying suitable locations to produce crushed rock aggregates, borrow earth suitable for road works and fillings and also the inadequate supply of sand is one of the factors delaying construction projects. Realizing this, an attempt was made in 2006 by the then Ministry of Highways to identify suitable locations to establish quarries and crushers with Asian Development Bank’s (ADB) assistance. But now at most of these sites, houses have been built as no proper action was taken to protect the sites.”

The Chamber proposed a remedial action plan which stresses on “a survey undertaken jointly by Geological Survey and Mines Bureau (GSMB), Road Development Authority (RDA) and Central Environment Authority (CEA) to identify suitable locations to establish quarries and crushers and also to borrow earth on a district basis. No houses should be allowed to be constructed within the danger zone at these locations.”

Sand requirement

“The total annual quantity of sand required cannot be obtained from river beds alone. The sustainable annual supply of river sand will be around 10 million cubic metres (MCM). As such at least eight MCM should be met from washed and sieved sea sand and balance 2 MCM from manufactured sand. At present sea sand is harvested and supplied only by Sri Lanka Land Reclamation and Development Corporation (SLLRDC) at Muthurajawela. But at this location it will be difficult to supply more than three MCM. Therefore, at another two locations, possibly Chilaw and Batticaloa, harvesting and processing should be undertaken. From Batticaloa arrangements should be made to transport sand by train to a location close to Colombo. This will save on transport costs at the same time generating revenue to CGR.”

Prime material

Cement, sand and aggregate are basic needs for any construction industry. Sand is a prime material used for preparation of mortar and concrete and which plays a major role in mix design. There is a scarcity of river sand given erosion of rivers and associated environmental issues.

Many countries which dealt with huge construction industries in the past have faced similar issues; however, they have also found solutions for the issues – both short-term and long-term.

Sri Lanka as a country with a comparatively huge construction industry (in comparison with the size of the economy and the extent of the land and resources) is heavily dependent on river sand (about 70-80%) and pit sand. A researcher who has made scientific calculations on sand requirement says, “The current demand for fine aggregates (sand) is 40 million cubic meters per annum and this is without considering the ‘Port City’ and any other special projects. However the supply is not over 15 million cubic meters.”

There is already a deficit which may come through ‘illegal’ ways - as there is no proper method in place to check the quality of the sand/aggregates. There are no guidelines and a supervisory body. This leads to issues with the quality of the final products too, says an industry expert, Altaf Halil.

He says many researchers are finding different materials to replace sand and one of the major materials is quarry stone dust. Using different proportion of these quarry dust along with sand the required concrete mix can be obtained.

Non-availability of sand

The non-availability or shortage of river sand will affect the construction industry, hence there is a need to find the new alternative material to replace the river sand, such that excess river erosion and harm to the environment is prevented.

Experts and researchers say that the policy makers should urgently study and take a decision on alternative solutions for river sand, before it is too late.

Some of the alternatives include dune sand, off shore sand, rock sand, artificial sand and manufactured sand. “Recycling of construction waste is also an effective way to manufacture sand. Several companies are already doing this, but in a small way. This is a major area that should be encouraged by the government,” Halil said.

Research on artificial sand

Sri Lankan researchers have done extensive research and found out ways to manufacture sand for the construction sector.

Globally many countries have gone through the issue of finding sand for the construction industry as the natural resources were shrinking as a result of over-mining. The demand for natural sand had been a huge issue in our neighbour India too. Several years ago, river sand mining was banned in most states in India and consequently Indian manufacturers were successful in producing an eco-friendly variety of sand from slag, a by-product generated from iron-making furnaces.

Halil said, other countries started looking for alternatives for natural sand (river sand) mainly because of the environmental impact from ‘excessive harvesting’ of natural sand (river sand) to cater to the increased demand in the construction industry with research begun as far back as the early 70s. Since then almost every country which faced with this situation has addressed the issues on a short and long term basis according to their local conditions. “We too started facing this situation almost ‘two decades’ ago and have had seminars and workshops to educate the stakeholders, professionals and the authorities.”

“Today in addition to find adequate amounts of sand for the construction industry (as per the demand), we are also faced with multiple Environmental issues that need immediate attention. These include land erosion, river level going below sea level and thereby river water getting contaminated with sea water, no proper water supply to the agricultural sector and flooding, he added.

“Our construction activities are huge, the quality of construction is at risk and the cost of construction is also shooting upwards. If we are to address this fine aggregate (sand) issue genuinely, all these can be addressed and cost of construction too can be brought down by at least 20 - 30% with much improved quality standard,” Halil said.

Many countries with huge construction industries have found short-term to long-term solutions for the issue. Almost all those countries are now focusing on carbon-less, eco friendly building structures.

This is another way to reduce the use of natural sand. Some short term solutions the other countries have tried out include the use of dune and offshore sand. Quality-wise, the dune and off shore sand falls quite short of the usual quality.

Meanwhile the long-term solutions can include reducing the use of fine aggregates (sand) altogether in all construction related activities and manufacturing sand.

Experts say final strength of the concrete made using artificially manufactured sand is better compared with natural sand. It can be used in all construction activities and can replace river sand easily.

Can this be done in Sri Lanka?

Building a house of their own is a dream of any family in Sri Lanka. But it’s a costly affair, given the salary structures and cost of living in the country at present.

Therefore, there is a major need in the construction industry to offer cost-effective housing/building construction methods for the benefit of the people.

Such cost-effective building methods can help reduce construction costs also and cut the use of sand in the industry drastically. At the beginning the cost cuts may appear insignificant. However, with a proper system in place, the costs can be calculated as a major saving component in the economy, said Halil who is an engineer by profession.

Industry dialogue

“When you take the overall issue, there are obstacles to introducing some of the short term solutions. To overcome that situation, the industry stakeholders and policymakers should start a dialogue and continue the dialogue to educate people and disseminate the positive messages.”

Sri Lanka’s construction industry experts point out the shortage of availability of quality sand has impacted the construction activity in a major way. It could be severe in the future. The industry leaders last month wrote to the President asking him to look at the sand issue (among many others) as a priority.

President, CCI Wijeratne said, the growth of the construction industry is pivotal to the economy’s growth. Therefore, it is paramount the government takes a policy decision on the matter and encourage companies to invest on R and D and production of artificial sand.

As major initiative, India provided loan facilities to companies and individuals who entered into the business of making sand.

 


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